Proper nutrition requires ingestion and absorption of vitamins, minerals, and food energy in the form of carbohydrates, proteins, and fats. Dietary habits and choices play a significant role in the quality of life, health and longevity. It can define cultures and play a role in religion.
Many people choose to forgo food from animal sources to varying degrees (e.g. flexitarianism, vegetarianism, veganism, fruitarianism) for health reasons, issues surrounding morality, or to reduce their personal impact on the environment, although some of the public assumptions about which diets have lower impacts are known to be incorrect. Raw foodism is another contemporary trend. These diets may require tuning or supplementation such as vitamins to meet ordinary nutritional needs.
A particular diet may be chosen to seek weight loss or weight gain. Changing a subject's dietary intake, or "going on a diet", can change the energy balance and increase or decrease the amount of fat stored by the body. Some foods are specifically recommended, or even altered, for conformity to the requirements of a particular diet. These diets are often recommended in conjunction with exercise. Specific weight loss programs can be harmful to health, while others may be beneficial (and can thus be coined as healthy diets). The terms "healthy diet" and "diet for weight management" are often related, as the two promote healthy weight management. Having a healthy diet is a way to prevent health problems, and will provide your body with the right balance of vitamins, minerals, and other nutrients.
A healthy diet is one that helps maintain or improve overall health. A healthy diet provides the body with essential nutrition: fluid, adequate essential amino acids from protein, essential fatty acids, vitamins, minerals, and adequate calories. The requirements for a healthy diet can be met from a variety of plant-based and animal-based foods. A healthy diet supports energy needs and provides for human nutrition without exposure to toxicity or excessive weight gain from consuming excessive amounts. Where lack of calories is not an issue, a properly balanced diet (in addition to exercise) is also thought to be important for lowering health risks, such as obesity, heart disease, type 2 diabetes, hypertension and cancer.
Various nutrition guides are published by medical and governmental institutions to educate the public on what they should be eating to promote health. Nutrition facts labels are also mandatory in some countries to allow consumers to choose between foods based on the components relevant to health.